Skip to content

Eosinophil Count (Manual Differential Blood Count)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to allergies and inflammatory conditions.

Quick summary

["Eosinophil counts help identify potential allergic reactions, infections, or inflammatory disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
34957-1
Short code
Eosinophil # CSF Manual
Synonyms
Eosinophil # CSF Manual
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Matters

Eosinophils are a type of immune cell that can rise in response to allergies, parasitic infections, or certain chronic conditions like asthma or inflammatory bowel disease. This test helps doctors track how your body is responding to these triggers.

What to Expect Before the Test

No special preparation is needed for this test. A simple blood draw is performed, usually from a vein in your arm. The sample is then examined under a microscope to count eosinophils manually.

Common Conditions Monitored

Elevated eosinophil counts may suggest conditions like allergic reactions, parasitic infections, certain cancers (e.g., leukemia), or autoimmune diseases. Low counts might indicate immune suppression or other underlying health issues.

How Results Are Interpreted

Results are typically reported as a percentage or absolute count of eosinophils in your total white blood cell count. While reference ranges vary by lab, doctors use clinical context to assess results alongside other symptoms and tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Eosinophils play a key role in defending against parasites, regulating allergies, and managing chronic inflammation. Abnormal counts can signal underlying immune dysfunction or exposure to irritants.

Short name

Eosinophil Count

Frequently asked questions

What causes eosinophil counts to rise?
Elevated eosinophil counts can result from allergies, asthma, parasitic infections, certain cancers, or autoimmune diseases. Stress, medications, or recent infections may also temporarily affect levels.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on lab processing times. Follow-up with your healthcare provider to discuss findings.
Can diet or medications affect eosinophil counts?
Dietary changes or medications (e.g., steroids, certain antibiotics) may influence immune cell activity, but they rarely alter eosinophil counts significantly. Always discuss potential effects with your doctor.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy